1. Field of the Invention
The present invention relates to a printer control film used for setting conditions of exposure for printing onto a printing paper, images recorded on a photographic film, and to a film carrier onto which such a printer control film is loaded. The present invention also relates to a method for managing such a printer control film.
2. Description of the Related Art
In a photographic printer, in order to obtain color prints each having an optimum density and tone, the processing performance of each processing solution such as developing solution, is strictly controlled, and for each printing apparatus conditions of exposure are set for printing onto a printing paper (color paper) images recorded on a negative film. Such exposure conditions are obtained from standard exposure conditions which provide proper prints through exposure when each image has a standard density. That is, the standard exposure conditions are compensated so as to obtain an optimum density and color balance regardless of variations in image density caused by overexposure or underexposure.
The standard exposure conditions for providing color prints each having an optimum density and tone must be correct when a color paper having a different emulsion number is used, when a printing lamp is replaced, when developing solution is changed, when colors of photographs are changed due to a turning of the seasons, or the like. Further, when the exposure conditions vary due to dirt, degradation, or replacement of an optical system including a light adjusting filter, a lamp, a reflector, etc., the standard exposure conditions and compensation values therefor must be corrected.
When such standard exposure conditions or their compensation values are set or corrected, a developed film which is obtained by photographing a predetermined object under preset exposure conditions (printer control film) is used, and a so called "conditioning operation" is performed using the printer control film. In the conditioning operation, exposure conditions are set or corrected such that an image recorded on the printer control film is printed in a desired state. The printer control film used for conditioning is a so-called "Bull's-eye" having a circular image at the center of a frame, which is formed by photographing a gray object. The Bull's-eye is loaded onto a film carrier, in the same manner as in the case of ordinary photographic film, so as to carry out exposure for printing onto a printing paper the image recorded on the Bull's-eye. Through this process, a photographic print is obtained. The density of the image on the photographic print is measured and compared with that of an image on a previously prepared standard print (reference print). Based on the results of the comparison, the exposure conditions are set.
However, when the image recorded on the Bull's-eye discolors or becomes dirty, the conditioning operation becomes impossible to be carried out accurately even if the discoloration or dirt is slight. Since images on a plurality of Bull's-eyes differ slightly from one another, perform conditioning operation must be avoided using a Bull's-eye for a different photographic printer. Management for such a Bull's-eye is performed using a label which is attached to part of the film and on which is displayed a start time of use, a time limit for use, a photographic printer to be conditioned, and the like. Therefore, it is difficult to perform the management accurately, and there is a large possibility of bringing about problems of erroneous use of a Bull's-eye which has passed its time limit for use or which has reached the usable limit (a predetermined number of times of use), or erroneous use of a Bull's-eye used for conditioning another photographic printer.